Transmission of electrical impulses.



' TRANSMISSI J. s. RICHMOND. I OH OF ELECTRICAL IMPU'LYSES.

APPLICATION FILED APR. 27, 1901.

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PATENTED APR. 26, 1904.[

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. UNITED STATES batenteo April 26, 1904.

PATENT OFFICE.

TRANSMISSION OF ELECTRICAL IMPULSES- SPECIFICATION forming part ofLetters Patent No. 758,106, dated April 26,1904.

Application filed April 27, 1901.

To all whom it may concern.-

Be it known that I, JOHN STANLEY R1011- MOND, a subject of His BritannicMajesty King Edward VII, residing at New York, in the borough ofManhattan and State of New. York, have invented certain new and usefulImprovements Relating to the Transmission of Electrical Impulses; and Ido hereby declare the following to be a full, clear, and exact,description of the same, reference being.

had to the accompanying drawings, forming a part of this specification,and to the letters of reference marked thereon.

This invention relates to the art of transmitting electrical impulsesthrough electrical transmission mediums, and more especially suchimpulses as are utilized in the arts of telegraphy and telephony,although not restricted to these arts, the objects of the inventionbeing to enable such impulses to be transmitted through long cables,vsubmarine or otherwise, and to render their transmission through shortcables more expeditious and efiicacious.

The transmission of electrical impulses, particularly in telegraphy andtelephony, has hitherto been effected by whatI term single transmissiont'. 6., the transmission of electrical impulses produced telephonically,telegraphically, or otherwise with one generating device through onecircuit, (metallic or otherwise,) in which casecapacity has proven to behighly detrimental, especially where a cable or cables form a portion orportions of the working circuit or circuits. To prevent detrimentalinductive efiects, certain conditions must be established in thecablethat is to say, the sheath of the cable being zero potential, orthe potential of the earth, the im pulses in the conductor or conductorsmust at contiguous points be in potential equally above and equallybelow the zero potential, or

potential of the sheath. Obviously the desired end cannot be attainedwith a singlewire earth return nor with a metallic circuit unless theimpulses in the two conductors at contiguous points be in potentialequally above and equally below the potential of the sheath, and thiscan only be attained by a system in Serial No. 57,821. (No model.)

7 which the two conductors of a metallic circuit have an equal capacityin regard to the sheath and when the meeting points of the two halves ofthe system, one of which includes one conductor and the other the otherconductor, are maintained at the zero potential, which points may betermed the medial points. If these medial points be not so maintained,then while the impulses in the conductors may be respectively'above andbelow a potential intermediate to the potential .in the conductorsthemselves, yet that intermediate potential may not correspond to thezero potential, and if not the aforesaid detrimental effects will occur.

In carrying out the present invention I employ what Iterm doubletransmission'that is, the transmission through two contiguoustransmission mediums of equal impulses simultaneously varied in equalratio, the impulses at contiguous-points in the two transmission mediumsbeing simultaneously equal in potential measured from the zeropotential, but differing in this, that the potential of the one is aboveand that the potential of the other is below such zero potential,whereby no detrimental capacity eflects are producedin so far as theimpulses being transmitted are concerned. In otherwords, in accordancewith my invention the cable, considered as a condenser within a sheathor shield, has its contiguous points when in operation in an idealcondition from a charged-condenser point of view, Which condition cannotresult in any detrimental so-called capacity effect, which detrimentalso-called capacity 'efiect is but the attempt of the cable-condenser toattain such ideal condition, which ideal condition cannot be establishedor maintained by transmissum, as heretofore practiced.

In the practical application of the invention two contiguous conductorsare employed, forming the transmitting media of the line, suchconductors being as nearly as practicable similar in all respects,especially as to their resistance and their capacity considered as acondenser, the medial points where such transcontiguous to but insulatedfrom the conduc- 'tors, such as the cable-sheath, by an earthconnection, and in connection with such conductors there are providedmeans for transmitting through said conductors impulses simultaneouslyequal at contiguous points in the conductors,.but of opposite potentialwith respect to the zero potential, or potential of the mediumsurrounding but insulated from the conductors, and means for making theimpulses manifest at the receiving-station.

In the drawings illustrative of the invention, Figures 1, Q, 8, 4, 5, 6,and 7 are dia grammatic illustrations of the application of the presentinvention to an impulse-transmitting system or systems. Fig. 8represents a cross-section at a point in a cable when the impulses inthe conductors at such a point are respectively 5() and 50+.

In said drawings the cable portion of the system is indicated by theletter A, while two conductors in the cable forming portions of a pairof transmitting mediums are indicated by 'the letters B and G, suchconductors being equal and so arranged in the cable as to have from acondenser point of view equal capacities under equallyinfluencingconditionsthat is, arranged in the same relation to the sheath (0 of thecable, as shown in Fig. 8in other words, having their points of similarproximity to the sheath equal,&c. Cables having two or more pairs ofwires should have the core constructed similar to those diagrammaticallyillustrated on page L66 of a work entitled Ailfmmal of Telephony, byPreece and Stubbs, edition of 1898. The cable A extends between the two'stations, and, as shown, the transmitting-stations are indicated by theletter D and receiving-stations by the letter F; but while the drawingsshow a transmittingstation at one end and a receiving-station at theotherend it will be understood that each station may be both atransmitting and a receiving station.

The conductors B and C are as nearly as practicable of the sameresistance and as equal as possible in all respects. They form,respectively, portions of the two transmitting mediums, which mediumswhen joined together at each end form a working circuit, and anyinstrument introduced into or influencing one transmission medium hasits counterpart in the other transmission medium, the object being tohave both transmission mediums, considered from the medial points orpoints where the two transmission mediums meet, in all respects equal toeach other. WVith this object in View the receiving instrument orinstrumentality for making the impulses manifest or the impulse-creatinginstrumentality may be introduced as a bridge between two points, one ineach transmission medium, such points being electrically equidistantfrom the meeting-point of the two transmission mediums, in which casewhen operative one medial point would be at the center of theinstrument-as shown, for instance, by the diagrammatic illustration ofthe receiving instrument F, Figs. 1, 2, 4E, and 5. If so desired, tworeceiving instruments may be introduced, one on each side of the medialpoint, as shown by (Elr G in 3 and 6, either or both of whichinstruments may be utilized. At the transmittingstation similarconditions are established--- that is to say, the instrument forcreating the impulses may bridge points electrically equidistant fromthe medial pointer an instrument be located on each side of the medialpoint. The impulses may be created by a primary generator, such as adynamo, or by an impulse instrumentality in conjunction withcurrent-generating means. In Figs. 1 and 2 equal batteries H and I,located in the respective transmission mediums, are shown, theimpulse-creating instrumentality in Fig. 1 being transmittinginstruments K K, one located on each side of the medial point. In Fig. 2a single transmitting instrument L, bridging points electricallyequidistant from the medial point, is shown. In Figs. 2) and 6 twodynamos M M are shown, one on each side of the medial point. In 4 and 5a single dynamo N is shown bridging points electrically equidistant fromthe medial point. The balanced conditions having been established, thenwhen the circuit is working the tension in one conductor may be said tobe l potential and that in the other potential; but in cablework to alarge extent and in other work to a lesser extent condenser conditionsare encountered, and this not only between the conductors, but alsobetween the conductors and the medium surrounding and more or lessinsulated from them. In cablework such surrounding medium insulated fromthe conductors is the sheath. The potential of such sheath must,therefore, be taken into account, and to prevent detrimental condensereffects the potential in the respective conductors must at everycontiguous point be simultaneously as equally above (-I) in the one as,tl1at in the other is below the zero (Oi or 0) potential of the sheathof the cable, As illustrated, this is accomplished through cstab'lishing an unvarying zero (Ozt) potential at the medial points in thesystem, as by a ground or earth connection, which may be the connectionP from the medial point at the transmitting-station, as in Figs. 1 and3, or the connection Q from the medial point of the receiving-station,as in Fig. 6. The desired result may be accomplished by a ground orearth connecting the middle point electrically of a resistance bridgingpoints electrically equidistant fromthe medial point when in op eration,especially where the transmitting iustrument is located at the medialpoint, such resistance acting as a shunt and so arranged that sufficientso-called electricity shall operate in the transmitting instrument orthe receiving instrument if the earth or ground connection is located atthe receiving-station. Figs. 2, 4, and 5 illustrate such an arrangement.In Figs. 2 and 5 each earth connection is made to the middle point ofthe resistance R,which resistance R bridges points electricallyequidistant from the medial point situated in the transmittinginstrument.

Fig. 7 is a diagrammatic illustration of the application of theinvention to a common-battery telephonic system showing two subscribers.T T are subscribers sets, B C and B 0 being two conductors passingthrough the cables A A. B and B are connected, through aretardation-coil Y, to a battery H. O and C are connected, through aretardation-coil Y, to a battery H equal to H. The remaining terminalsof H and H are connected together and such connection connected toearth.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is

1. In a system of electrical transmission, two conductors forming thesides of a metallic circuit, combined with means for maintaining zeropotential at the meeting-points of the two conductors; substantially asdescribed.

2. In a system of electrical transmission, two equal conductors formingthe sides of a metallic circuit, combined with a ground connection formaintaining zero potential at the meeting-point of the two conductors;substantially as described.

3. In a system of electrical transmission, two equal conductors, formingthe sides of a metallic circuit, combined with means for maintainingzero potential at the meetingpoints of the two conductors, and means forcreating impulses in the said conductors simultaneously equal-atcontiguous points but differing in this, that the impulses in oneconductor are equally above as those in the other are below themaintained Zero potential; substantially as described.

4. In a system of electrical transmission, equal contiguous insulatedconductors equally insulated from and surrounded by a sheath repeatedlygrounded, said conductors forming sides of a metallic circuit, themeeting-points of said conductors grounded whereby zero potential ismaintained at that point and equal impulse-creating means located onopposite sides of the zero-points, said impulse-creating meanssimultaneously creating impulses in one conductor above and in the otherconductor impulses equally below the zero potential, substantially asdescribed.

5. In a system of electrical transmission, equal contiguous conductorsinsulated from each other and connected together to form a metalliccircuit, a ground connection at the meeting-point of the conductors andequal generators included in said conductors equidistant electricallyfrom the zero-point said generators being in series with each other inthe circuit; substantially as described.

6. In a system of electrical transmission, equal contiguous conductors,forming the sides of a metallic circuit and an earth connection wheresaid equal conductors meet, whereby zero potential is maintained at thatpoint, combined with means for creating impulses simultaneously equal atcontiguous points in the two conductors, respectively, but differing inthis, that'the impulses in one conductor are equally above as those inthe other are below zero potential; substantially as described.

7. In a system of electrical transmission, equal insulated conductorsforming sides of a metallic circuit, a ground surrounding saidconductors, a ground connection at the meeting-point of said conductorswhereby earth potential is maintained at that point, and means forcreating impulses simultaneously equal at contiguous points in the saidconductors one of said points being in one conductor and the other pointin the other conductor, but differing in this that the impulses in oneconductor are in potential as equally above as those in the otherconductor are below said earth potential; substantially, as described.

8. In a system of electrical transmission, equal contiguous insulatedconductors equally insulated from and in similar proximity to a mediumrepeatedly grounded, said conductors forming sides of a metallic circuitand having their meeting-point grounded whereby Zero potential isestablished at that point, electricalimpulse-generating apparatus solocated in series in such circuit and so that the electrical medialpoint in such apparatus is electrically equidistant from zero-point ofsaid circuit and other apparatus in series in such circuit so locatedthat the electrical medial point in such other apparatus is electricallyequidistant from zero-point of said circuit for utilizing the impulsesgenerated; substantially as described.

JOHN STANLEY RICHMOND. Witnesses: I

ALEXANDER S. STEWART, JOSEPH B. CHURCH.

